1. Field of the Invention
The present disclosure relates to a light source module having a light-emitting element, such as a light-emitting diode (LED), as a light source and that is suitable for use as a light source of a lamp fitting, such as an illuminating lamp of a vehicle.
2. Description of Related Art
In a recent vehicle, a related art lamp that uses a light-emitting element, such as an LED, as a light source element has been proposed in order to save energy expended in operation of the lamp when the lamp is used in head lamps and/or tail lamps. An example of such a related art lamp is described, for example, in Japanese Patent Unexamined Publication No. JP-A-2005-209537. In a lamp of this type, an LED is mounted, for example, on a power feeding substrate, and the substrate is implemented on a module substrate, to thus make up a light source module. Alternatively, an LED might be mounted directly on a module substrate, to form a light source module. The thus-configured light source module is built in a lamp unit including a reflector and a collecting lens, and is used as a light source of in a related art lamp unit.
In the related art lamp unit having a light source module of this type, a luminous point of an LED element serving as a light source is narrower than a luminous point of an incandescent electric lamp, and the like. Hence, in order to acquire a desired luminous intensity distribution characteristic, a luminous point of an LED element must be positioned with high accuracy. Accordingly, in JP-A-2005-209537, circular-arc projections are provided on a portion of a substrate making up a light source module, and the projections are brought into contact with a portion of an LED seat of the lamp unit, thereby horizontally positioning the light source module on the lamp unit.
In JP-A-2005-209537, the light source module is mounted on a seat and supported while being pinched on the seat by a clip of a leaf spring. The light source module is concurrently pressed toward one side of the seat by spring force of the clip so as to bring the projections on the substrate into contact with a side wall surface of the seat, thereby positioning the light source module. However, when using the clip, there is a disadvantage in that vibrations and the like developed in a vehicle would cause the clip to fall or cause a deterioration of the spring force of the clip that would result in a decrease in pinching force, which in turn might cause the light source module to move over the seat or fall off from the seat. For these reasons, it is possible to fastening the light source module to the seat by means of screws.
When the light source module is fastened with a screw, the light source module does not largely move over the seat or fall off from the seat. However, if the light source module is fixedly supported simply by means of screws, the positioning accuracy of the light source module is deteriorated by the tolerance between the screws and threaded holes. Therefore, the light source module is positioned and fastened with screws while being held in a positioned state.
However, in this case, an operation for holding a positioned state and an operation for fastening the light source module with screws must simultaneously be performed, which makes an assembly operation complicated and difficult. In particular, when the light source module is fastened with screws, the force used to fasten the screws is transmitted to the light source module, which makes it easy to develop rotational force in the light source module. The rotational force might pose difficulty in holding the light source module in the positioned state, which would also cause a decrease in positioning accuracy.